Vehicle jack

ABSTRACT

A jack is provided which derives lifting power from vehicle motion. The lifting action of the main upright leg is regulated and made positive by the action of an auxiliary starting leg.

lJnited States Patent King 51 Mar. 28, 1972 54] VEHICLE JACK 1,460,229 6/1923 Deal ..2s4/94 [72] Inventor: l-iansford D. King, 5754 Via Margarita, ggg Santa MariaCalifi 93454 22 Filed; No 27 1970 Primary Examiner-Andrew R. Juhasz Assistant Examiner-David R. Melton PP 93,040 Attorney-Evert A. Autrey [52] [57] ABSTRACT A jack is provided which derives lifting power from vehicle [58] motion. The lifting action of the main upright leg is regulated and made positive by the action of an auxiliary starting leg. [56] References Cited 8 Claims, 5 Drawing Figures UNITED STATES PATENTS 1,288,846 12/1918 Dannenbring ..254/94 PATENTEnmza m2 SHEET 1 OF 2 FIG. If

FIG 3.

INVENTOR HANSFORD D. KING aw 0/ W HIS ATTORNEY PATENTEDMAR28 1972 3.652.056

SHEET 2 OF 2 INVENTOR.

HANSFORD D. KING BYMQ HIS ATTORNE VEHICLE JACK BACKGROUND OF THE INVENTION This invention relates to a jack of the type powered by the motion of the vehicle with which it is used, and more particularly to a jack having a main support leg and a shorter auxiliary starting leg.

STATE OF THE PRIOR ART Jacks operated by vehicle motion have been known for many years. In the simplest form a single leg, which is pivotally secured to the vehicle frame, is lowered so the free end reaches the ground or pavement. If the free end remains in place as the vehicle moves, the movement will cause the leg to become vertical and the desired lifting action will take place. However, the free end without manipulation generally does not stay in place but merely slides along as the vehicle moves. This is particularly apt to happen when the leg is sufficiently long to raise the vehicle high enough so that the tires clear the ground. Shortening the leg makes initiation of the elevating process somewhat easier but the vehicle tire then remains firmly in contact with the ground when the jack is at its highest point. Previous attempts to provide a simple mechanism with positive initiation of elevating action and a high lift have been unsuccessful.

SUMMARY OF THE INVENTION The elevating mechanism of the invention employs a main support leg and an auxiliary starting leg attached to a common frame. The legs are linked so that the action of the main leg is influenced by the position of the starter leg. Fixed and movable pins are provided for locking the legs in a generally horizontal direction for travel and for locking the main leg in a generally vertical direction for supporting the vehicle with which it is used.

An object of the invention is to provide a compact, positive action jack.

An additional object is to provide ajack which is simply and reliably actuated by vehicular motion.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view showing the jack in storage position;

FIG. 2 is a similar view showing the jack in position as first released;

FIG. 3 is a similar view showing the jack in the action of lifting the vehicle;

FIG. 4 is a similar view showing the jack in full elevating position; and

FIG. 5 is a perspective view showing ajack frame.

DETAILED DESCRIPTION OF THE INVENTION The apparatus shown in FIGS. 1 through 4 comprises a frame bolted to vehicle frame member 12 by means of bolts 14. Starter leg 22 pivots on the upper end about pin 24. Main support leg 28 pivots at the upper end about pin 30 and is provided with a generally flat sole plate 32 at the lower end thereof. A chain 34 or other flexible member links the two legs, the ends of the chain being conveniently secured to the two legs at about their respective midpoints. The vehicle wheel 36 is shown in FIG. 2 as supporting frame member 12. Fixed pin 40 braces the side plates of frame 10 and also limits the travel of legs 22 and 28. Bore 42 is fitted with pin 44 for holding the two legs in a predetermined attitude in the storage and full elevating positions.

In the operation of the jack thus far described, the assembly is maintained in storage position as shown in FIG. I through the action of pin 44 which supports starter leg 22 and main support leg 28 in a generally horizontal position. When it is desired to elevate frame member 12, pin 44 is pulled allowing the legs to fall and assume the positions shown in FIG. 2. Pin 44 is inserted into the opening in the lower end of leg 22, and the length of the combination is adjusted so that starter leg 22 will assume an angle relative to the ground of about 45 or less when first lowered. This attitude ensures that the lower end of pin 44 will not slide as the vehicle is moved but will engage positively even the smoothest surface immediately. Pin 44 may be held in place by bolt 45 through leg 22 as shown in FIG. 2, or alternatively the bolt may be placed in one of the bores in pin 44 so that the bolt fits against the bottom end of leg 22 thus limiting the depth of insertion into leg 22. This arrangement allows pin 44 to fall freely when leg 28 is supporting the vehicle and the starter leg is clear of the ground. The vehicle is then caused to move in a direction to actuate the lifting mechanism; this direction of movement of the vehicle is to the right for the orientation of jack elements shown in the figures. The engagement of pin 44 with the ground becomes more positive as leg 22 begins to support a considerable portion of vehicle weight and to assume a nearly vertical position as shown in FIG. 3. However, when this position or attitude of the starter leg is reached it is seen that chain 34 has become taut making it impossible for the lower end of main support leg 28 to slide along the ground as vehicle movement continues and the initial raising action of main support leg 28 takes place. Sole plate 32 thus engages the ground positively and main support leg 28 gradually becomes more nearly vertical as the orientation shown in FIG. 4 is approached. Vehicle travel is stopped when the main support leg becomes vertical and further movement of the legs 22 and 28 is prevented by the blocking or limiting action of pin 40. Pin 44 is then placed in bore 42 and vehicle movement in either direction is thus prevented. If blocking pin 44 is secured in place as by a padlock, for example, through a bore in the end of the pin, the vehicle cannot be moved away by thieves as long as locking pin 44 is in place. It has been found that the jack can be efficiently operated by frail and inexperienced vehicle drivers; a heavy-duty boat trailer bearing a large load can be raised simply and quickly using the above described procedure. The positiveness of action is shown by the fact that a number of installations have one jack disposed on each side of a trailer, and the elevating action of both jacks operated simultaneously is such that lifting starts and ends at the same time for both sides of the vehicle.

The jack frame shown in FIG. 5 may be simply and economically constructed of a flat member 48 and a bent member 54 joined as by welding and provided with matching holes in the two parts for receiving the various bolts and pivot pins. The unsymmetrical hole pattern requires that left hand and right hand frames be used for opposite sides of a vehicle. An alternative construction employs two flat plates which may be bolted on opposing sides of a vehicle frame member.

Most commercially-made boat trailers and many other trailers of all types have frame members which are about the same height above the ground so that fixed leg lengths are feasible for the great majority of installations. It is obvious that both the starting leg 22 and main support leg 28 can be made adjustable in length using known expedients such as threaded extensions or pin fasteners fitting into matching holes in extension parts. However, the modification of the starter leg only, as shown in FIGS. 1 through 4, is useful where the jack is used on ground that is level or somewhat uneven. The jack above described is particularly useful on trailers of all types but is effective on other vehicles and in fact on any structure that needs to be elevated and which can be moved to actuate the starter and main support legs of the jack.

While the present invention has been described in only a few embodiments, it will be apparent to those skilled in the art that the practice of the present invention may assume many other forms without departing from the spirit and scope thereof.

What is claimed is:

1. A jack for raising a vehicle comprising:

a. a jack frame secured to a portion of said vehicle;

b. a starter leg swingably secured to said jack frame;

c. a main support leg swingably secured to said jack frame;

and d. a flexible member joining said starter leg to said main support leg whereby the initial raising action of said main support leg is controlled by the attitude ofsaid starter leg. 2. The invention defined in claim 1 comprising in addition fixed blocking means in said jack frame for limiting the travel of said main support leg in one direction and removable blocking means in said jack frame for limiting the travel of said main support leg in the opposite direction.

3. The invention defined in claim 2 wherein said removable blocking means is an adjustable extension of saidstarter leg.

4. The invention of claim 1 comprising in addition a generally flat sole plate secured to the lower end of said main support leg.

5. The invention of claim 1 wherein said flexible member is a chain.

6. The invention of claim 1 wherein said flexible member is secured to the approximate midpoints of said starter leg and said main support leg.

7. The invention of claim 1 wherein said starter leg is ad- 0 justable in length. 

1. A jack for raising a vehicle comprising: a. a jack frame secured to a portion of said vehicle; b. a starter leg swingably secured to said jack frame; c. a main support leg swingably secured to said jack frame; and d. a flexible member joining said starter leg to said main support leg whereby the initial raising action of said main support leg is controlled by the attitude of said starter leg.
 2. The invention defined in claim 1 comprising in addition fixed blocking means in said jack frame for limiting the travel of said main support leg in one direction and removable blocking means in said jack frame for limiting the travel of said main support leg in the opposite direction.
 3. The invention defined in claim 2 wherein said removable blocking means is an adjustable extension of said starter leg.
 4. The invention of claim 1 comprising in addition a generally flat sole plate secured to the lower end of said main support leg.
 5. The invention of claim 1 wherein said flexible member is a chain.
 6. The invention of claim 1 wherein said flexible member is secured to the approximate midpoints of said starter leg and said main support leg.
 7. The invention of claim 1 wherein said starter leg is adjustable in length.
 8. The invention of claim 1 wherein said starter leg and said main support leg are adjustable in length. 